1. Field of the Invention
This invention relates to wall anchors and anchoring systems for cavity walls. More particularly, the invention relates to systems for cavity walls subjected to high-wind loading conditions.
2. Description of the Prior Art
Emergent conditions foster innovation. Dangerous conditions persist—tragedy strikes—change occurs. Whether it is a traffic light at a busy intersection or a less than substantial seawall facing a hurricane, society seems naturally to procrastinate.
Hurricane Katrina formed Aug. 23, 2005 and reached peak strength on Aug. 28, 2005 with one-minute sustained winds of 175 mph. In December 2005, the Federal Emergency Management Agency (FEMA) issued an analysis of Attachment of Brick Veneer in High-Wind Regions. Even with such a remarkable background, the anchoring of brick veneer to a variety of backup walls faces a dearth of standards.
The FEMA analysis of brick veneer failures modes are, in turn, categorized as human failures—used wrong fasteners; misaligned tie during installation; ties not installed; improper tie spacing; and used mortars of poor quality—and as mechanical failures—one-piece, corrugated ties (lacking compressive strength); fastener failure; structure provided inadequate embedment; and corrosion failures.
In the past, Ronald P. Hohmann and Ronald P. Hohmann, Jr., the inventors hereof, have solved several similar technical problems. Their inventions have been in response to changes in Uniform Building Code provisions and to investigations into effects of various forces, particularly lateral forces, upon brick veneer construction. The resultant products distributed under the Seismiclip® and DW-10-X® trademarks (manufactured by Hohmann and Barnard, Inc., Hauppauge, N.Y. 11788) have become widely accepted in the industry.
Later patents in this area assigned to Hohmann and Barnard, Inc., include U.S. Pat. Nos. 5,454,200 ('200); 6,789,365 ('365); 6,925,768 ('768); and, 6,941,717 ('717). The Hohmann '200 patent was directed to adding reinforcement to the outer wythe and improving the uniformity of the distribution of lateral forces therein. This patent did not resolve high-strength requirements at the inner wythe or teach about the insulation/wall anchor interrelationship.
In the Hohmann '365 patent, low-profile anchor configurations are taught. This development arose from, inter alia, the Energy Code Requirement, Chapter 13 (78 CMR, Seventh Edition; Boston, Mass.). With this requirement the need for higher R-value insulation perforce increased the cavity size and the technological improvement taught by the patent resolved the high-strength vs. high-span dilemma created thereby.
Hohmann '768 and '717 effectuated structural changes to the wall anchor shown in Hohmann, U.S. Pat. No. 4,598,518 and enabled the maintenance of insulation integrity with surface mounted, pronged veneer anchors.
In the course of preparing this disclosure several patents became known to the inventors hereof. The following patents are believed to be relevant and those not discussed hereinabove are discussed further as to the significance thereof.
PatentInventorIssue Date7,017,318Hohmann et al.Mar. 28, 20066,941,717Hohmann et al.Sep. 13, 20056,925,768Hohmann et al.Aug. 9, 20056,789,365Hohmann et al.Sep. 14, 20046,279,283Hohmann et al.Aug. 28, 20016,209,281RiceApr. 3, 20015,816,008HohmannOct. 15, 19985,456,052Anderson et al.Oct. 10, 19955,454,200HohmannOct. 3, 19955,408,798HohmannApr. 25, 19955,392,581Hatzinikolas et al.Feb. 28, 19954,875,319HohmannOct. 24, 19894,869,038CataniSep. 26, 19894,598,518HohmannJul. 8, 19864,473,984LopezOct. 2, 19844,373,314AllenFeb. 15, 19834,021,990SchwalbergMay 10, 19773,377,764StorchApr. 16, 1968
It is noted that with some exceptions these devices are generally descriptive of wire-to-wire anchors and wall ties and have various cooperative functional relationships with straight wire runs embedded in the interior and/or exterior wythe. Several of the prior art items are of the pintle and eyelet/loop variety.
Storch—U.S. Pat. No. 3,377,764—Issued Apr. 16, 1968
Discloses a bent wire, tie-type anchor for embedment in a facing exterior wythe engaging with a loop attached to a straight wire run in a backup interior wythe.
B. J. Schwalberg—U.S. Pat. No. 4,021,990—Issued May 10, 1977
Discloses a dry wall construction system for anchoring a facing veneer to wallboard/metal stud construction with a pronged sheetmetal anchor. Like Storch '764, the wall tie is embedded in the exterior wythe and is not attached to a straight wire run.
J. A. Allan—U.S. Pat. No. 4,373,314—Issued Feb. 15, 1983
Discloses a vertical angle iron with one leg adapted for attachment to a stud; and the other having elongated slots to accommodate wall ties. Insulation is applied between projecting vertical legs and adjacent angle irons with slots being spaced away from the stud to avoid the insulation.
Lopez—U.S. Pat. No. 4,473,984—Issued Oct. 2, 1984
Discloses a curtain-wall masonry anchor system wherein a wall tie is attached to the inner wythe by a self-tapping screw to a metal stud and to the outer wythe by embedment in a corresponding bed joint. The stud is applied through a hole cut into the insulation.
M. J. Catani—U.S. Pat. No. 4,869,038—Issued Sep. 26, 1989
Discloses a veneer wall anchor system having in the interior wythe a truss-type anchor with horizontal sheetmetal extensions. The extensions are interlocked with bent wire pintle-type wall ties that are embedded within the exterior wythe.
R. Hohmann—U.S. Pat. No. 4,875,319—issued Oct. 24, 1989
Discloses a seismic construction system for anchoring a facing veneer to wallboard/metal stud construction with a pronged sheetmetal anchor. Wall tie is distinguished over that of Schwalberg '990 and is clipped onto a straight wire run.
Hatzinikolas et al.—U.S. Pat. No. 5,392,581—Issued Feb. 28, 1995
Discloses a cavity-wall anchor having a conventional tie wire for mounting in the brick veneer and any-shaped sheetmetal bracket for mounting vertically between side-by-side blocks and horizontally atop a course of blocks. The bracket has a slit which is vertically disposed and protrudes into the cavity. The slit provides for a vertically adjustable anchor.
Hohmann—U.S. Pat. No. 5,408,798—issued Apr. 25, 1995
Discloses a seismic construction system for a cavity wall having a masonry anchor, a wall tie, and a facing anchor. Sealed eye wires extend into the cavity and wire wall ties are threaded therethrough with the open ends thereof embedded with a Hohmann '319 (see supra) clip in the mortar layer of the brick veneer.
Anderson et al.—U.S. Pat. No. 5,456,052—Issued Oct. 10, 1995
Discloses a two-part masonry brick tie, the first part being designed to be installed in the inner wythe and then, later when the brick veneer is erected to be interconnected by the second part. Both parts are constructed from sheetmetal and are arranged on substantially the same horizontal plane.
Hohmann—U.S. Pat. No. 5,816,008—Issued Oct. 15, 1998
Discloses a brick veneer anchor primarily for use with a cavity wall with a drywall inner wythe. The device combines an L-shaped plate for mounting on the metal stud of the drywall and extending into the cavity with a T-head bent stay. After interengagement with the L-shaped plate the free end of the bent stay is embedded in the corresponding bed joint of the veneer.
Rice—U.S. Pat. No. 6,209,281—Issued Apr. 3, 2001
Discloses a masonry anchor having a conventional tie wire for mounting in the brick veneer and sheetmetal bracket for mounting on the metal-stud-supported drywall. The bracket has a slit for adjustability of the tie wire, which slit is vertically disposed in the cavity when the bracket is mounted on the metal stud. For installation, this anchor requires an opening through the sheetrock into the cavity.
Hohmann et al.—U.S. Pat. No. 6,279,283—Issued Aug. 28, 2001
Discloses a low-profile wall tie primarily for use in renovation construction where in order to match existing mortar height in the facing wythe a compressed wall tie is embedded in the bed joint of the brick veneer.
Hohmann et al.—U.S. Pat. No. 7,017,318—Issued Mar. 28, 2006
Discloses a high-span anchoring system for a cavity wall wire-to-wire anchor. The structure includes wall reinforcements in both inner and outer wythes. Wire wall anchors extending from the inner wythe and passing through the insulation are compressed to optimize sealing thereabout.
None of the above provide the masonry cavity wall construction system for an inner masonry wythe and an outer facing wythe with high-span anchoring wire formatives as described hereinbelow.